Additional file 2: Table S1. Phenotypic data of T1 are expressed as mean ± SD, T1 refers to 21 DAS. The data represents the results of three biological repetitions. Table S2. Phenotypic data of T2 are expressed as mean ± SD, T2 refers to 24 DAS. The data represents the results of three biological repetitions. Table S3. Quality evaluation of RNA-seq reads and mapped to reference genome. Table S4. Information on upregulated and downregulated DEGs of 21 DAS hybrid F1 (AM, CM, HM, HW) and their parents (A, C, H, M, W). Table S5. Information on upregulated and downregulated DEGs of 24 DAS hybrid F1 (AM, CM, HM, HW) and their parents (A, C, H, M, W). Table S6. Specific gene information for the classification of expression patterns of 12 types of ELD genes at 21 DAS. Table S7. Specific gene information for the classification of expression patterns of 12 types of ELD genes at 24 DAS. Table S8. Results of significant GO enrichment of F1 relative to the parent of the parental-ELD gene at 21 DAS. Table S9. Results of significant GO enrichment of F1 relative to the parent of the parental-ELD gene at 24 DAS. Table S10. Information on DEGs of strong hybrids and weak hybrids at 21 DAS. Table S11. The results of the significantly enriched GO terms of the DEGs shared by the two pairs of strong and weak hybrids at 21 DAS. Table S12. The results of the significantly enriched KEGG pathways of the DEGs shared by the two pairs of strong and weak hybrids at 21 DAS. Table S13. Information on DEGs of strong hybrids and weak hybrids at 24 DAS. Table S14. The results of the significantly enriched GO terms of the DEGs shared by the two pairs of strong and weak hybrids at 24 DAS. Table S15. The results of the significantly enriched KEGG pathways of the DEGs shared by the two pairs of strong and weak hybrids at 24 DAS. Table S16. Total genes in the yellow module. Table S17. KEGG results of significant enrichment of genes in the yellow module. Table S18. Hub genes in the yellow module. Table S19. GO terms that were significantly enriched with respect to hub genes in the yellow module. Table S20. Specific information about the sequence of the quantitative primers of randomly selected genes.

Additional file 2: Table S1. Phenotypic data of T1 are expressed as mean ± SD, T1 refers to 21 DAS. The data represents the results of three biological repetitions. Table S2. Phenotypic data of T2 are expressed as mean ± SD, T2 refers to 24 DAS. The data represents the results of three biological repetitions. Table S3. Quality evaluation of RNA-seq reads and mapped to reference genome. Table S4. Information on upregulated and downregulated DEGs of 21 DAS hybrid F1 (AM, CM, HM, HW) and their parents (A, C, H, M, W). Table S5. Information on upregulated and downregulated DEGs of 24 DAS hybrid F1 (AM, CM, HM, HW) and their parents (A, C, H, M, W). Table S6. Specific gene information for the classification of expression patterns of 12 types of ELD genes at 21 DAS. Table S7. Specific gene information for the classification of expression patterns of 12 types of ELD genes at 24 DAS. Table S8. Results of significant GO enrichment of F1 relative to the parent of the parental-ELD gene at 21 DAS. Table S9. Results of significant GO enrichment of F1 relative to the parent of the parental-ELD gene at 24 DAS. Table S10. Information on DEGs of strong hybrids and weak hybrids at 21 DAS. Table S11. The results of the significantly enriched GO terms of the DEGs shared by the two pairs of strong and weak hybrids at 21 DAS. Table S12. The results of the significantly enriched KEGG pathways of the DEGs shared by the two pairs of strong and weak hybrids at 21 DAS. Table S13. Information on DEGs of strong hybrids and weak hybrids at 24 DAS. Table S14. The results of the significantly enriched GO terms of the DEGs shared by the two pairs of strong and weak hybrids at 24 DAS. Table S15. The results of the significantly enriched KEGG pathways of the DEGs shared by the two pairs of strong and weak hybrids at 24 DAS. Table S16. Total genes in the yellow module. Table S17. KEGG results of significant enrichment of genes in the yellow module. Table S18. Hub genes in the yellow module. Table S19. GO terms that were significantly enriched with respect to hub genes in the yellow module. Table S20. Specific information about the sequence of the quantitative primers of randomly selected genes.

Cytoplasmic male sterility is primarily caused by chimeric genes located in the mitochondrial genomes. Previously, orf288 had been cloned as a CMS-associated gene in the hau CMS line. However, neither the specific abortive stage nor the molecular function of orf288 had been determined in hau CMS. To better understand the mechanism of hau CMS in Brassica, we further characterized the hau CMS line and found defective mitochondrial arrest during the development of archesporial cells during the L2 stage, leading to male sterility. Expression level of the orf288 transcript was higher in the male sterility line than in the restorer line, although no significant differences were apparent at the protein level. The toxicity region of ORF288 is located near the N-terminus and represses E. coli growth. However, transgenic expression of different portions of ORF288 indicated that the region that causes male sterility resides between amino acids 73 and 288, which do not result in growth inhibition when expressed in E. coli. Transcriptome analysis revealed a wide range of genes involved in anther development and mitochondrial function that were differentially expressed in the hau CMS line. This study provides new insights into hau CMS mechanism by which orf288 affects Brassica juncea fertility.